1. Field of Invention
The invention relates to an automatic lock device for the optical module of a scanner and, in particular, to a lock device automatically locking/unlocking the optical module triggered by plugging/unplugging the power plug.
2. Related Art
Due to great advances in the opto-electronic technology, we have digital devices such as scanners, digital cameras, digital video recorders, etc. In particular, scanners have been widely used in paperless office environments because they can quickly covert paper documents into electronic files.
In an ordinary scanner, there are at least a case, a cover, an optical module, and a transmission mechanism. The case is provided with a scan window. The cover is pivotally installed on one side of the case. The optical module and the transmission mechanism are installed inside the case. The optical module which is driven by the transmission module is installed on a carrier so that the optical module can have a reciprocal motion within the range of the scan window. Since the optical module is a movable device relative to the scanner, the manufacturer often installs a lock on the optical module or the carrier in order to avoid damages or defocus of the optical module due to transportation. The lock fixes the optical module (carrier) before the scanner is shipped out. The consumer has to remove the lock before the first use.
However, even with the clear instruction provided by the scanner manufacturer that tells the user to remove the lock before use, many users still forget this step and start the scanner before removing the lock. This often results in damages to the transmission mechanism or the optical module.
To solve this problem, some manufacturers install the lock in the vicinity of the connection port. When the lock fixes the carrier, it blocks the connection port at the same time. The user has to remove the lock in order to connect the cable or power plug to the connection port. This can prevent the user from starting the scanner before removing the lock. However, this method is purely designed for preventing damages during shipping from the manufacturer and when the user first operates the machine. The user may not remember or bother to put on the lock in case he or she needs to move the scanner from one place to another.